The proposed project investigates the patterns and social psychological determinants of substance use among adolescent children of alcoholics (COAs). The high prevalence of COAs among individuals treated for chemical dependency suggests that effective primary prevention efforts aimed at this group could produce substantial public health benefits. There are strong theoretical reasons to believe that adolescent COAs are at high- risk for alcohol and substance use. However, because most research has studied general adolescent population, little is known about the nature, extent, and time course of this risk. Moreover, little is known about the processes that underlie substance use and abuse in this population. The proposed study will follow a sample of 250 COA and 200 non-COA adolescents and their families over a three-year period. The study will identify potentially modifiable risk and protective factors that influence substance use among COA and non-COA adolescents, and will determine whether these factors act in unique ways among COAs. Finally, the study will evaluate the utility of negative affect regulation models of substance use against competing theoretical alternatives. The results of this project will have important implications for both the timing and the content of substance use prevention programs aimed at high-risk adolescents.